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Приглашенные
доклады

С. Г. Каршенбойм. Лэмбовский
сдвиг в атоме водорода. XV
Конференция: Фундаментальная атомная спектроскопия. Звенигород.
1996.

S. G. Karshenboim. The
hydrogen Lamb shift and the proton radius.
In Proceedings of the International Workshop Hadronic
Atoms and Positronium in the Stardard Model (Dubna, 1998).
Ed. By M. A. Ivanov et al., Dubna (1998)
224231. Электронный препринт: hepph/0008137.

S. G. Karshenboim. The
proton radius as measured by optical methods.
In Proceedings of the 15th Students' Worsshop on Electromagnetic Interactions.
Bosen
(1998)
pp.87101.

S. G. Karshenboim. Hydrogenic
Bound States. Invited talk at International
Symposium Lepton
Moments. Heidelberg, 1999.
Прозрачки.

S. G. Karshenboim. Precise
Physics of Simple Atoms. Atomic Physics
17 (AIP conference proceedings 551) Ed. by E. Arimondo et al. AIP, 2001,
pp. 238253. Электронный препринт: hepph/0007278.
Invited talk at International conference on Atomis Physics 2000
(Florence). Abstract.

S. G. Karshenboim. Laser
spectroscopy of simple atoms and precision tests of bound state QED.
Invited talk at 3rd Simposium on Modern Problems of Laser Physics.
Novosibirsk, 2000.
Электронный
препринт:
physics/0008215.
Abstract.

S. G. Karshenboim. g
factor of a bound electron in hydrogenlike ions.
An invited talk at ITAMP Workshop Wave
Functions and QED Effects in FewElectron Atoms. Harvard, 2000.
Прозрачки.

S. G. Karshenboim. Possible
laboratory search for variation of fundamental constants.
An invited talk at 250. WEHeraeus
Seminar Presision Experemints and Fundamental Constants in Physics,
Bad Honnef 2001.
Abstract.

S. Karshenboim. Precision
Study of Positronium, Presented
at 9th International Workshop on Slow Positron Beam Techniques for Solids
and Surfaces (SLOPOS), Dresden, 2001.
Abstract.

S. G. Karshenboim,
Simple
atoms, Quantum electrodynamics and fundamental constants. PSAS'2002
(St. Petersburg, 2002).

S. G. Karshenboim,
Laboratory
search for variation of fundamental constants. Australian
Institute of Physics: 15th
Biennial Congress (Sydney, 2002).

S. G. Karshenboim,
Simple
atoms: QED tests and fundamental constants. Australian
Institute of Physics: 15th
Biennial Congress (Sydney, 2002).

S. G. Karshenboim,
Time
and physical constants.
International
Colloquium on Time and Matter (Venice, 2002).

S. G. Karshenboim,
QED
theory of hydrogenlike atoms. Third
Workshop on Hadronic Atoms (CERN, 2002).

S. G. Karshenboim,
Variation
of the FineStructure Constant. HYPER
SYMPOSIUM (Paris, 2002).

S. Karshenboim,
Precision
study of positronium and precision tests of the bound state QED. (Workshop
on Positronium Physics, ETH Zurich, 2003).

S. G. Karshenboim, Precision
tests of QED and the finestructure constant,
an
invited talk at International
Workshop on Fundamental Interactions (ECT* European Centre for
Theoretical Studies in Nuclear Physics and Related Areas, Trento, 2004).

S. G. Karshenboim, P. Fendel, V. G. Ivanov,
N. Kolachevsky and T. W. Haensch, 2s
Hyperfine Structure in Hydrogen and Deuterium: a Precision Test of QED,
an
invited talk at Hydrogen atom 3: Precision Physics of Simple Atomic
Systems (Mangaratiba, 2004).

S. G. Karshenboim,
Laboratory
searches for a time variation of fundamental constants,
an invited talk at 9th
Summer Institute at Gran Sasso National Laboratory on Particles, Gravity
and Cosmology, 2004.

Тезисы
приглашенного доклада на международную конференцию ICAP 2000
Precise
Physics of Simple Atoms
Savely
G. Karshenboim
D. I. Mendeleev Institute for Metrology,
St. Petersburg, Russia
and
MaxPlanckInstitut fuer Quantenoptik,
Garching, Germany
Simplicity
of “simple” atoms has been for a while a challenge to precision theory
and experiment. Are the simple hydrogenlike atomic systems simple enough
to be calculated with an accuracy, appropriate to compete to the best experimental
results? That is a question, that theorists have tried to response. The
most simple atoms are different twobody bound systems with a low value
of the nuclear charge: Z = 1 (hydrogen, deuterium, muonium and positronium)
and Z = 2 (singlecharged ions of helium3 and helium4) etc. We
present state of art in physics of simple atoms and discuss in detail theoretical
and experimental status of studying such atoms.
In
particular, we consider few theoretical problems:

Small parameters for simple atoms are lower than
1/100 (=
1/137, =1/207
etc), however, most of known expansions over them used to behave not quite
well because of large logarithms (ln(1/)
~
~ 5) and large numerical coefficients. Appearance of increasing powers
of these large logarithms make any estimation of a theoretical accuracy
to be a hard problem.

Two kinds of higherorder QED corrections have not
been known uptodate and limit the precision of the present theoretical
evaluations. One of them arises from expansions of the electron twoloop
selfenergy contribution in strengh of the Coulomb interaction ().
That is a problem to compute the Lamb shift in the hydrogen, helium ion
and some higherZ atomic systems. Similar higherorder (in ())
terms should appear for calculations of a bound electron gfactor
in hydrogenlike ions at Z~2030.

The other important task is to evaluate radiativerecoil
contributions with essential binding effects. Such contributions are important
for the hyperfine structure in muonium and for positronium spectrum.

Important problem is contributions beyond QED and,
in particular, influence of strong interactions. For instance, our possibility
to do any calculation for the hydrogen and deuterium atoms is completely
limited now by our knowledge of the proton and deutron structure.
Most
of these questions and a more broad range of problems in physics of simple
atoms were considered at a Satellite meeting to the ICAP (Hydrogen
Atom, 2: Precise Physics of Simple Atomic System) and in their book
of abstracts one can find detail on theoretical and experimental status
of physics of simple atoms, including hydrogen, muonium, positronium, helium,
fewelectron ions at different Z, muonic and exotic atoms, antihydrogen.
Several metrological problems due to precison spectroscopy and determination
and possible variation of fundamental constants were also among the topics
of the satellite meeting.

Тезисы
приглашенного доклада на международную конференцию MPLP’2000
Precision
spectroscopy of simple atoms and tests of the bound state QED
Savely
G. Karshenboim
D. I. Mendeleev Institute for Metrology,
St. Petersburg, Russia
and
MaxPlanckInstitut fuer Quantenoptik,
Garching, Germany
Precision laser spectroscopy
of simple atoms (hydrogen, deuterium, muonium, positronium etc) provides
an opportunity to precisely test Quantum Electrodynamics (QED) for bound
states and to determine different fundamental constants with a high accuracy.
The talk is devoted to a comparison of theory and experiment for the bound
state QED.
The
QED for free particles (electrons and muons) is a wellestablished theory
designed to perform different calculations of particle properties (like
e. g. anomalous magnetic moment) and of scattering cross sections. In contrast,
the theory of the bound states is not so well developed and it needs further
precision tests.
Experimental
progress during the last ten years has been mainly due to laser spectroscopy
and, thus, the bound state QED tests are an important problem associated
with modern laser physics.
The
QED theory of the bound states contains three small parameters, which play
a key role: the QED constant ,
the strength of the Coulomb interaction
and the mass ratio m/Mof
an orbiting particle (mainly – electron) and the nucleus. It is not possible
to do any exact calculation and one needs to use some expansions over some
of these three parameters.
The crucial theoretical problems
are:

The development of an effective approach to calculate
higherorder corrections to the energy levels.

Findig an effective approach to estimate higherorder
corrections to the energy levels.
The difference between these
two problems is very important: any particular evaluations can include
only a part of terms and we must learn how to determine the uncertainty
of the theoretical calculation, i. e. how to estimate corrections that
cannot be calculated.
We consider higher order QED corrections, our
knowledge on which determines the accuracy of the bound state QED calculations.
We particularly discuss: the Lamb shift in hydrogen and light hydrogenlike
atoms, hyperfine structure in muonium and positronium, 1s2s
and fine structure of positronium
etc.
After recent calculations of the oneloop, twoloop
and threeloop corrections to the Lamb shift in the hydrogen atom the main
uncertainty comes from higher order twoloop contributions of the order .
They contain a large logarithm
and the leading term with the cube of the logarithm is known [1]. The uncertainty
due to the uncalculated double logarithms is estimated as 2 ppm.
A
specific combination of the Lamb shifts
is
important [2] for the evaluation of data of optical measurements from Garching
and Paris, obtained by means of twophoton Dopplerfree laser spectroscopy.
The uncertainty in this difference is also determined by unknown terms,
but the leading terms which includes a squared logarithm is known [2].
The
hyperfine structure of the ground state in the muonium atom is a precisely
measured value. The uncertainty of the calculation is due to unknown corrections
of the fourth order. Some of these, including the large logarithms (
or ),
are known [3] and nonleading terms limit the uncertainty of the theoretical
expression as 0.05 ppm. The uncertainty arises from the unknown nexttoleading
radiativerecoil ()
and pure recoil ()
terms. The largest uncertainty comes from a calculation of the leading
term because of the lack of a precise knowledge of the muontoelectron
mass ratio. One way to determine this ratio is the 1s2s
muonium experiment.
For
the case of the positronium spectrum there are a number of value which
were or are under precision experimental study. In all cases the uncertainty
of the positronium energy (n = 1, 2) is known up to .
The only double logarithm is known to the next order. The inaccuracy originates
from the nonleading terms (single logarithm and constant) of radiative
and radiativerecoil corrections of order .
In our talk we discuss briefly also some other
values. The brief review shows that now the crucial corrections in the
bound state QED are:

higher order twoloop corrections;

radiativerecoil and pure recoil terms of order ,
the calculation of which involves an essential part of the QED, binding
and twobody effects .
Most problems concerning
the study of simple atoms were discussed at the recent Hydrogen
atom, 2 meeting, which took place this June in Italy and one can
find more references on the subject therein [4].
References:

S. G. Karshenboim, JETP 76 (1993) 541.

S. G. Karshenboim, Z. Phys. D 39 (1997) 109.

S. G. Karshenboim, Z. Phys. D 36 (1996)
11.

Hydrogen Atom
II: Precision Physics of Simple Atomic Systems. Book of abstracts
(ed. by S. G. Karshenboim and F. S. Pavone), Castiglione della Pescaia,
2000.

Тезисы
приглашенного доклада на международный семинар 250. WE
Possible
laboratory search for variation of fundamental constants
Savely
G. Karshenboim
D. I. Mendeleev Institute for Metrology,
St. Petersburg, Russia
and
MaxPlanckInstitut fuer Quantenoptik,
Garching, Germany
A possibility of variation of
value of some physical constants was proposed long time ago. Up to now
there has been no reasonable common model to describe such a variation.
Recent attempts to detect some variations have led to limitations for fractional
variation of some constants on level of 10^{3}10^{5}
during the lifetime of our Universe.
Different options for the search
for possible variations are considered in the talk and a short overview
of the results obtained with several methods is given. Their advantages
and disadvantages are discussed with respect to simultaneous variations
of all constants in both time and space in range 10^{8}10^{10}
yr. A few possibilities for the laboratory search are suggested [1].
In particular, we propose some experiments with the hyperfine structure
interval in atomic hydrogen, deuterium and ytterbium171 and in some atoms
with small nuclear magnetic moments. Since most of precisely measured frequencies
are due to hyperfine structure transitions we pay special attention to
interpretation of such measurements in terms of variation of fundamental
constants.
Reference:
1. S. G. Karshenboim, Can. J.
Phys. 78, 639 (2000). 
